Mobile devices are incredibly widespread in today's society. For example, people use cellular phones, smart phones, personal digital assistants, laptop computers, pagers, tablet computers, etc. to send and receive data wirelessly from countless locations. Moreover, advancements in wireless communication technology have greatly increased the versatility of today's mobile devices, enabling users to perform a wide range of tasks from a single, portable device that conventionally required either multiple devices or larger, non-portable equipment.
For example, mobile devices can be configured to determine what environment (e.g., restaurant, car, park, airport, etc.) a mobile device user may be in through a process called context determination. Context awareness applications that perform such context determinations seek to determine the environment of a mobile device by utilizing information from the mobile device's sensor inputs, such as GPS, WiFi and BlueTooth®. In many scenarios, classifying audio from the mobile device's microphone is highly valuable in making context determinations, but the process of collecting audio that may include speech can raise privacy issues.